(a) Field of the Invention
The present invention is related to a low drag bike seat stem, and more particularly to one comprised of a joint and a tube in briolette shape for the stem to be adapted with an insertion cap to be inserted to the seat tube for adjusting and securing its height.
(b) Description of the Prior Art
Usually, a bike seat stem relates to an integrated structure comprised of a joint and a tube. Though the configuration may differ, the tube of the prior art indicates a round retractable tube to be inserted and secured to the seat tube. As illustrated in FIG. 7 of the accompanying drawings of the present invention, a seat stem with low drag of the prior art is essentially comprised of an integrated joint and tube. Wherein, the upper section of the tube is modified so to indicate a sharp style. Said upper section having a sharp tube 10 is thus reserved as the seat tube; and the lower section 20 of the tube, to be inserted and locked into the seat tube.
However, the sharp tube 10 of the prior art is not in circular, therefore, is prevented from being locked deep into the circular, hollow seat tube. Consequently, the length to permit descending of the seat tube is restricted to where not lower than the sharp tube 10. Similarly, if the seat tube is elevated, the lower section 20 of the seat stem is partially exposed to increase the drag. Accordingly, the low drag bike seat stem fails an arbitrary elevation for its full length. Furthermore, as the size of tube varies, there is the absence of a bike seat tube with an inner diameter generally applicable to the entire seat stem.
The primary purpose of the present invention is to provide a bike seat stem comprised of a joint and a tube with the full length of the tube having a briolette shape of gradually reducing to one side so that a low drag bike seat stem is formed once the joint is inserted and incorporated to the upper end of the tube. The entire tube can be extruded for easier production and saving production cost.
Another purpose of the present invention is to provide a low drag bike seat stem, which is adapted to an insertion cap built-in bike seat stem, to allow free elevation of the full length of the stem to be locked into the bike seat tube as desired to ensure its low drag effects.